oscillating water temperature

[daffouk]

Hi,
My ideal isar boiler has developed a fault where the domestic hot water cycles between hot and tepid, damned annoying when in the shower.
My guess is that it is one of the thermistors, but not sure which one. Anyone any thoughts?

Dave[code:1][/code:1]

 

[Dan Robinson]

More likely a clogged plate heat exchanger.

 

[libby lou lou]

That was the last problem with my isar, which dan correctly diagnosed, cheers dan!!!.

 

[daffouk]

More likely a clogged plate heat exchanger.

Thanks Dan, I have a spare one of those, I'll give it a try. Dave

 

[daffouk]

More likely a clogged plate heat exchanger.

I got round to swopping out the heat exchanger over the weekend and it has cured the hot/cold cycling problem: thanks for the tip.

I was surprised that the old exchanger wasn't visibly clogged up, nor did much muck come out when I jetted it through, but whatever, the boiler is sorted now - till the next thing that goes wrong with it, not my best buy that boiler, 5 years old and hardly any of the original components still in it